Abstract
Greenhouse control computers are an essential part of modern greenhouse operation. Climate, irrigation and nutrient supply must be controlled, in an economically way, to produce the best crop conditions. Current research on CO2 enrichment and optimal growth strategies implies the use of powerful tools, either based on hardware or software. This paper describes the implementation of a distributed data acquisition and control system for computerised agricultural management systems. To accomplish with the emergent and future tendencies in this area the network uses different communications platforms to achieve low-cost, flexibility, and functionality. The techniques and tools, that provide to the user a transparent, friendly and intuitive Graphical User Interface will be also presented. Copyright (C) 1998 IFAC.

Abstract
This paper proposes a genetic algorithm (GA) to generate trajectories for robotic manipulators. The objective is to minimize the ripple in the time evolution of robot positions and velocities. Moreover, the manipulator is required to reach a predefined goal without colliding with obstacles in the workspace. The article presents the results for several redundant and non-redundant robot manipulators.

Abstract
Cooperative Go-evolution using Structured Genetic algorithms is proposed as a new technique to solve the problem of identification of discrete-time multivariable systems, using a closed-loop Multi-Input Single Output simultaneous testing procedure. This identification technique is illustrated by identifying a two-inputs two-outputs plant model, and simulation results are presented that allows to conclude about the convergence effectiveness of the cooperative co-evolutionary identification technique when compared with a single population Structured Genetic Algorithm applied to the same identification problem.

Abstract
A soil moisture sensor (SMS) was built around RISC-like microcontroller and common peripherals to perform data acquisition, signal processing, configuration, fault-detection and data communication with a control/management system. The SMS employs capacitance and heat-pulse techniques to determine the soil water content. The sensor uses the capacitance technique as the main method while the heat-pulse readings, acquired at a lower rate, are used for calibration and fault detection purposes. The temperature sensors and the heater were assembled in a four-needle probe. Several experiments were conducted for different types of soil. The results showed that this sensor could be applied in an effective way to measure the soil water content. Several tests are being performed to conclude about the sensor dependence with soil temperature and chemical composition as well about its long-term stability.

Abstract
Soil water content has a direct influence on the cooling and growth mechanisms of the plants. Crop evapotranspiration is majoring influenced by solar radiation and the air temperature, humidity and movement. An efficient irrigation system must supply and maintain, at soil root zone of the plants, the adequate amount of water that best regulate the physiological mechanisms of the plant. For this purpose, an intelligent real-time greenhouse irrigation system was implemented which uses accurate sensors for measuring soil moisture, as well to determinate the crop evapotranspiration. To avoid loss of control, it was provided fault-detection capabilities to the soil moisture sensor and used a knowledge-based approach to estimate replacement values for the faulty sensors. A model-based controller was implemented to regulate the water content at the root zone of the plants. These tasks are very complex and difficult to meet, unless microcontroller and microprocessor systems are employed, such as in the integrated management irrigation system. The system comprises four modules: Sensor/Actuation, Acquisition and Data Validation, Data Correction, Model Based Controller, and Control Signals Generation. All the modules are linked and supervised by a higher-level supervision module to achieve an intelligent irrigation.

Abstract
In this paper it will be presented the aims and some of the results obtained in the project entitled "Development of Solutions for Instrumentation, Control and Management Applied to Agricultural and Fish Production Using Renewable Energies", sponsored by the Agriculture Ministry of Portugal. The experimental set-up is composed of three demonstration greenhouses and six aquaculture tanks for production of green beans, tomatoes and tilapias. Several actuators and sensors are connected to an acquisition and control network developed at the Engineering Department of the University of Tras-os-Montes and Alto Douro, Vila Real. The environmental factors controlled are: greenhouse inside air temperature and humidity, CO(2) concentration, and soil moisture. Dissolved O(2), pH, temperature and water nitrate concentration are also controlled in the fish tanks. Three types of heating systems are being used on the greenhouses and aquaculture tanks: a geothermal water source, a solar heat pump and a wood-gas combined heater. At the end of this project it is expected to achieve an efficient control in order to maximize the ratio production/costs. This implies the use of a supervisory module to perform high level management decisions. At this level, a decision support system helps the producer to establish the chemical treatment plans. This will also help to reduce environmental contamination as well production costs.